“This is not normal,” President Obama said Saturday of a shooting at a Planned Parenthood affiliate in Colorado Springs that killed three people and wounded nine others. The gunman, identified by the police as 57-year-old Robert Lewis Dear, held the clinic under siege for five hours with what was reported to be an “AK-47-style” weapon. Whether the shooter was an anti-abortion extremist wasn’t clear at the time, and Obama framed the tragedy exclusively in terms of its relationship to the nation’s gun-violence epidemic. But it was impossible to ignore that the shooter selected a target that had received mounting threats from anti-abortion extremists in recent months. The clinic was equipped with a safe room and bulletproof vests. Normal, no; but neither was the attack wholly unexpected.

Threats and attacks on abortion providers have spiked dramatically in the four months since an anti-abortion group calling itself the Center for Medical Progress released a series of heavily edited videos purporting to show Planned Parenthood officials “selling baby parts.” In September, the FBI noted an increase in cyber attacks and arsons, and warned that it was “likely criminal or suspicious incidents will continue to be directed against reproductive health care providers, their staff and facilities.” In October, a Planned Parenthood facility in California was fire-bombed, following three similar incidents in Illinois, Louisiana, and Washington. A clinic in New Hampshire was spray-painted with the word “murderer,” and then, a few weeks later, attacked by an intruder wielding a hatchet.

The clinic attacked Friday is operated by Planned Parenthood’s Rocky Mountains affiliate, whose medical director, Savita Ginde, was featured in one of the doctored CMP videos, allegedly “negotiating a fetal body parts deal, agreeing multiple times to illicit pricing per body part harvested, and suggesting ways to avoid legal consequences.” Several dozen protesters picketed her house in August after the video appeared, and left fliers around her neighborhood reading, “Savita Ginde Murders Children.” Deborah Nucatola, another doctor featured in the videos, has also been threatened. “I’ll pay ten large to whomever kills Dr. Deborah Nucatola. [She] should be summarily executed,” one anonymous commentator wrote online.

“The escalation has been alarming and frightening, to the extent of nothing I have seen in 20 years,” said Vicki Saporta, the president and CEO of the National Abortion Federation, which tracks threats and attacks against abortion providers. Friday’s mass shooting was the worst death toll in the history of clinic violence, which has comes in waves since the Supreme Court legalized abortion with its 1973 ruling in Roe v. Wade. The first reported arson occurred in 1976, and was followed by a series of bombings two years later. The violence escalated in the late 1980s and early 1990s, when extremists shifted their strategy to focus on harassing and attacking individual doctors. Dr. David Dunn, shot in Florida in 1993, was the first provider to be murdered. The last was Dr. George Tiller, who was killed in Kansas in 2009.

“We have a history of extremists in this country trying to intimidate women from trying to access, and intimidate providers from offering, those healthcare services. It’s a long history, and we’re in one of the most concerning stages of escalation that we’ve seen,” Saporta said. Since the release of the CMP videos the threats have become too numerous for NAF and individual facilities to handle on their own. The group hired an outside security firm, and is working with the Department of Justice’s Task Force Against Violence Against Health Care Providers. The man identified as the shooter was not on NAF’s “national radar screen,” but, Saporta said, “We were very, very concerned that something like this would happen.”

Anti-abortion groups including the National Right To Life Committee and Operation Rescue moved immediately to distance themselves from the Colorado shooting. So did CMP, whose founder David Daleiden insisted that the “Center for Medical Progress does not support vigilante violence against abortion providers.” (From the GOP presidential contenders, who’ve spent considerable time on the campaign trail trashing Planned Parenthood, the response was mostly crickets.) Yet those groups and many anti-abortion politicians have worked for years to demonize and dehumanize abortion providers. Rhetoric that likens doctors who provide legal health services to murderers, even Hitler, does more to incite violence than it does promote peace; and the line between anti-abortion activists who harass women “peacefully” and those that vandalize clinics has proven in practice to be somewhat slippery.

The CMP videos provoked a number of congressional and state-level investigations, but so far the only evidence of illegal activity implicates not Planned Parenthood but the anti-abortion activists who’ve responded to the videos with vandalism, arson, and possibly murder. The violent turn is certainly alarming, and Obama was right to link the Colorado shooting to “the easy accessibility of weapons of war.” Still, it’s worth remembering that anti-abortion terrorism exists on a continuum with subtler forms of intimidation and obstruction that have over the past several years made the legality of abortion nearly irrelevant for some women, particular those at the bottom of the economic ladder. Thanks to the courage of clinic staff, patients, and escorts, violence has not been the most effective means of ending the right to choose. But it is now making the right’s war on women more transparent than ever.